After its invasion in mid 1980s, the outbreak of the Russian wheat aphid (RWA) had caused serious damage to small grain production in the western United States including Wyoming. The aphid populations have diminished to insignificant levels in recent years in Wyoming, concurrent with the establishment and spread of parasitoids and dipteran predators. Currently, we are investigating seasonal occurrence of RWA natural enemies from April to October. We monthly place potted wheat infested with the RWA in several wheat fields in eastern Wyoming, as well as western Nebraska and northern Colorado. After a few days, pots were retrieved and foliage was clipped and placed in emergence canisters. This "bait" method effectively attracts and detects hymenopteran and dipteran natural enemies that specifically attack the RWA. In addition to two dominant parasitoid species (Aphelinus albipodus and Diaeretiella rapae) that were previously documented, we also detected two other parasitic wasps and at least two dipteran predators (syrphid and chamaemyiid species) attacking the RWA. These natural enemies occur at different times during the growing season and they may be collectively contributing for a season-long control of the RWA populations.
Species 1: Homoptera Aphididae Duraphis noxia (Russian wheat aphid)
Species 2: Diptera Syrphidae Eupeodes
Species 3: Diptera Chamaemyiidae Leucopis
Keywords: natural enemies, parasitic wasps
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